Recognition of Deep Band Modulated Consonants in Quiet and Noise in Older Individuals with and Without Hearing Loss

The purpose of the present study was to investigate the effects of temporal envelope enhancement using deep band modulation (DBM) on consonant identification scores (CIS) and transfer of features such as place of articulation, manner of articulation, and voicing.

Data were collected from four groups of ten participants each. These were grouped into younger (YNH) and older adult (ONH) individuals with normal hearing and younger (YHI) and older adult (OHI) individuals with hearing impairment who had mild to moderate sensorineural hearing loss. The CIS and transfer features for 21 vowel-consonant-vowel (VCV) syllables in unprocessed and DBM conditions with quiet and noise were obtained from each participant.

The results showed that consonant identification scores (CIS) in DBM conditions was significantly better than in unprocessed conditions in quiet and at 5 dB and 10 dB signal-to-noise ratios (SNRs). This was true in each group. Voicing was transmitted better than other features in each condition for all the groups except for the YHI group, for whom place of articulation was conveyed best in unprocessed conditions and manner of articulation was transmitted best in DBM conditions. Furthermore, in the YHI, ONH, and OHI groups, manner of articulation was conveyed better than place of articulation in both unprocessed and DBM conditions.

At reduced SNRs, cues from DBM enabled the listener to repeat the heard VCV syllables. The effect of aging and the combined effects of aging and hearing loss are partly lessened by DBM through enhancement of the manner of articulation in VCV syllables.